Speculative fiction and detective fiction have a lot in common -- they're both about digging down to the truth of matters. Fictional scientists and explorers, like detectives, follow clues and act on hunches. The truth is enshrouded in an ocean of red herrings and false trails. Plus, a lot of great science fiction authors, like Ray Bradbury and Robert Silverberg, also wrote detective novels, for money or as a change of pace."